diff --git a/Migration.md b/Migration.md
index 95d1b7d6..1dfeb9d5 100644
--- a/Migration.md
+++ b/Migration.md
@@ -13,3 +13,5 @@ release will remove the deprecated code.
    **Replacement**: include/ignition/utils/ExtraTestMacros.hh
 1. **Deprecated**: CMake functions and macros starting with `ign_`
    **Replacement**: CMake functions and macros starting with `gz_`
+1. **Deprecated**: `ignition` namespaces
+   **Replacement**: `gz` namespaces
diff --git a/doc/doxygen/api.in b/doc/doxygen/api.in
index 4a26d5e8..b0af4eb7 100644
--- a/doc/doxygen/api.in
+++ b/doc/doxygen/api.in
@@ -915,7 +915,7 @@ INPUT_FILTER           =
 # need to set EXTENSION_MAPPING for the extension otherwise the files are not
 # properly processed by doxygen.
 
-FILTER_PATTERNS        = *.hh="sed -e 's/inline\snamespace\s.*\s{$\|ignition::@IGN_DESIGNATION@::\|IGN_DEPRECATED([0-9\.]\+)\|IGNITION_@IGN_DESIGNATION_UPPER@_VISIBLE//g'"
+FILTER_PATTERNS        = *.hh="sed -e 's/inline\snamespace\s.*\s{$\|gz::@IGN_DESIGNATION@::\|IGN_DEPRECATED([0-9\.]\+)\|IGNITION_@IGN_DESIGNATION_UPPER@_VISIBLE//g'"
 
 # If the FILTER_SOURCE_FILES tag is set to YES, the input filter (if set using
 # INPUT_FILTER) will also be used to filter the input files that are used for
diff --git a/examples/comp_deps/src/AlmostEmpty.cc b/examples/comp_deps/src/AlmostEmpty.cc
index da65eaa2..bb7e0350 100644
--- a/examples/comp_deps/src/AlmostEmpty.cc
+++ b/examples/comp_deps/src/AlmostEmpty.cc
@@ -17,7 +17,7 @@
 
 #include <ignition/component_deps/Export.hh>
 
-namespace ignition
+namespace gz
 {
   namespace component_deps
   {
diff --git a/examples/core_nodep/src/AlmostEmpty.cc b/examples/core_nodep/src/AlmostEmpty.cc
index 0a1c6df8..8826778b 100644
--- a/examples/core_nodep/src/AlmostEmpty.cc
+++ b/examples/core_nodep/src/AlmostEmpty.cc
@@ -17,7 +17,7 @@
 
 #include <ignition/core_no_deps/Export.hh>
 
-namespace ignition
+namespace gz
 {
   namespace core_no_deps
   {
diff --git a/examples/core_nodep_static/src/AlmostEmpty.cc b/examples/core_nodep_static/src/AlmostEmpty.cc
index f55af640..8ff32660 100644
--- a/examples/core_nodep_static/src/AlmostEmpty.cc
+++ b/examples/core_nodep_static/src/AlmostEmpty.cc
@@ -17,7 +17,7 @@
 
 #include <ignition/core_no_deps_static/Export.hh>
 
-namespace ignition
+namespace gz
 {
   namespace core_no_deps
   {
diff --git a/include/ignition/utilities/SuppressWarning.hh b/include/ignition/utilities/SuppressWarning.hh
index e6b8619e..7b5a75da 100644
--- a/include/ignition/utilities/SuppressWarning.hh
+++ b/include/ignition/utilities/SuppressWarning.hh
@@ -15,8 +15,8 @@
  *
  */
 
-#ifndef IGNITION_UTILITIES_SUPPRESSWARNING_HH_
-#define IGNITION_UTILITIES_SUPPRESSWARNING_HH_
+#ifndef GZ_UTILITIES_SUPPRESSWARNING_HH_
+#define GZ_UTILITIES_SUPPRESSWARNING_HH_
 
 #include <ignition/utilities/detail/SuppressWarning.hh>
 
diff --git a/include/ignition/utilities/detail/SuppressWarning.hh b/include/ignition/utilities/detail/SuppressWarning.hh
index f69fb17b..0792498c 100644
--- a/include/ignition/utilities/detail/SuppressWarning.hh
+++ b/include/ignition/utilities/detail/SuppressWarning.hh
@@ -16,8 +16,8 @@
  */
 
 
-#ifndef IGNITION_UTILITIES_DETAIL_SUPPRESSWARNING_HH_
-#define IGNITION_UTILITIES_DETAIL_SUPPRESSWARNING_HH_
+#ifndef GZ_UTILITIES_DETAIL_SUPPRESSWARNING_HH_
+#define GZ_UTILITIES_DETAIL_SUPPRESSWARNING_HH_
 
 #include <ignition/utilities/SuppressWarning.hh>